What was the name of the remote-controlled robotic explorer which discovered the wreck of the Titanic?

D. Michael Harris and Jack Grimm had failed to find Titanic in their 1977 expedition, Robert Ballard had not given up hope and devised new technologies and a new search strategy to tackle the problem. The new technology was a system called Argo / Jason. This consisted of a remotely controlled deep-sea vehicle called Argo, equipped with sonar and cameras and towed behind a ship, with a robot called Jason tethered to it that could roam the sea floor, take close-up images and gather specimens. The images from the system would be transmitted back to a control room on the towing vessel where they could be assessed immediately.

The search required round-the-clock towing of Argo back and forth above the sea bed, with shifts of watchers aboard the research vessel Knorr looking at the camera pictures for any sign of debris. After a week of fruitless searching, at 12.48 am on Sunday 1 September 1985 pieces of debris began to appear on Knorr's screens. One of them was identified as a boiler, identical to those shown in pictures from 1911. The following day, the main part of the wreck was found and Argo sent back the first pictures of Titanic since her sinking 73 years before. The discovery made headlines around the world